Automatic Call Distribution systems (ACD) are widely used to answer calls quickly while using as few telephone network resources as possible. When an ACD receives a call, the goal is to distribute the call to the first available operator or service circuit that can handle the call. These systems work well until call handling resources are at or near capacity. Several systems have been proposed and/or implemented that reroute calls to other ACD systems or other resources within the same ACD system at such times. These systems generally rely on a priority list so that, when services are blocked at one ACD, the list is consulted and the call is sent to another ACD system on the list. There are various algorithms (such as time of day, day of week, etc.) used for determining which entry in the list is used. These schemes do not take into account the specific situation when network resources are not available to deliver the call to the alternate destination and resources are not available at the alternate destination. This results in more blocked calls and higher network occupancy. Therefore, a problem in the art is that no ACD system can route a call from a switch with blocked resources to another switch with a reasonable degree of certainty that the destination switch and path thereto is not blocked.